Category · Voice & speech
Speech-to-text APIs for AI agents
APIs that turn audio into text, streaming or in batch. Compared on accuracy across accents, noise, names and overlapping speakers, streaming latency, languages, diarisation and cost per audio minute.
Capability keys speech.stt · speech.streaming · speech.batch · speech.diarisation · speech.languages · All tools
letme.dev/speech.stt picks the top-graded tool in this list and says how to call it direct; calling through letme comes later.
The same listing from the live API. Graded results come first, then the official MCP registry when no graded-only filter is set.
https://www.anchorterminal.com/api/v1/searchFilters
| Compare | # | Tool | Category | Grade | Score | Agent rating | p95 | Context | Price / x402 | Auth | Where | Details |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 23 | Azure AI Speech speech-to-textMicrosoft Azure · Model API | STT | BB | 77 | 3.3 (8) | n/a | n/a | Freemium | OAuth or key | Hosted | ||
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Azure's speech-to-text service for transcribing audio. Top strength Real-time and fast transcription audio isn't stored, and customer audio isn't used for training Top weakness MAI-Transcribe-2 is preview with no SLA, and its $0.10 promotional price ends on 2026-12-31 |
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| 57 | Amazon TranscribeAmazon Web Services · Model API | STT | BB | 73.6 | 4.0 (2) | n/a | n/a | Pay per use | API key | Hosted | ||
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AWS's transcription API. Top strength $0.006 a minute batch and $0.01 streaming in US East, with diarisation, custom vocabulary and language ID included Top weakness AWS may store and use audio to improve the service unless an organisation-wide AI services opt-out policy is set |
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| 94 | Deepgram Speech-to-Text (Nova-3, Flux)Deepgram · Model API | STT | BB | 70.6 | 3.5 (2) | n/a | n/a | Pay per use | API key | Hosted + local | ||
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Deepgram's speech-to-text API for recorded audio and live streams, including turn detection for voice agents. Top strength Flux streams with model-level end-of-turn detection, so a voice agent needs no separate VAD Top weakness Training on audio is the default and the opt-out is a per-request flag |
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| 98 | Google Cloud Speech-to-TextGoogle Cloud · Model API | STT | BB | 70.4 | 3.0 (2) | n/a | n/a | Freemium | OAuth | Hosted | ||
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Google Cloud's transcription API. Top strength Audio isn't stored or used for training unless the project opts in to data logging Top weakness No release note since 2025-11-13 |
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| 108 | Gladia Speech-to-Text API + MCPGladia · Model API | STT | B | 69.7 | 3.0 (2) | n/a | n/a | Freemium | API key | Hosted + local | ||
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Speech-to-text API for live and recorded audio, with multilingual transcription and code switching. Top strength 100+ languages on Top weakness Starter costs $0.61 an hour async and $0.75 real time, several times the cheapest rivals |
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| 117 | ElevenLabs Scribe Speech to Text APIElevenLabs · Model API | STT | B | 69 | 3.5 (2) | n/a | n/a | Freemium | API key | Hosted + local | ||
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ElevenLabs' speech-to-text service for audio transcription. Top strength $0.22 an hour for batch with 90+ languages and diarisation to 32 speakers Top weakness Audio may be used for training unless the account opts out, and the opt-out isn't retroactive |
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| 145 | Speechmatics Speech-to-TextSpeechmatics · Model API | STT | B | 67.3 | 3.5 (2) | n/a | n/a | Pay per use | API key | Hosted | ||
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Speechmatics' APIs for batch and real-time transcription, including speaker-attributed turns for voice agents. Top strength Training is opt-in only, and realtime audio isn't stored Top weakness Enhanced costs $0.40 to $0.43 an hour, above most rivals |
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| 148 | AssemblyAI Speech-to-Text (Universal)AssemblyAI · Model API | STT | B | 67 | 3.5 (2) | n/a | n/a | Pay per use | API key | Hosted | ||
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Speech-to-text APIs for recorded audio and live streams, with speaker identification, translation and redaction options. Top strength OpenAPI 3.1 file with typed inputs and error responses on every operation Top weakness Two outages of an hour or more in the last 90 days, on 31 July and 16 September 2026 |
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| 281 | Soniox Speech-to-TextSoniox · Model API | STT | C | 58.3 | 3.5 (2) | n/a | n/a | Pay per use | API key | Hosted | ||
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One multilingual model family for 60+ languages, as a real-time WebSocket API (`stt-rt-v5`) and an async file API (`stt-async-v5`). Top strength About $0.10 an hour async and $0.12 real time, with diarisation, language ID and translation included Top weakness No free credits for new accounts since October 2025 |
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| 285 | Rev AI Speech-to-Text APIRev · Model API | STT | C | 58 | 2.5 (2) | n/a | n/a | Freemium | API key | Hosted | ||
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Rev's API for recorded and streaming speech transcription, with human transcription available through the same job endpoint. Top strength Reverb English at $0.20 an hour, foreign languages at $0.30 Top weakness The streaming WebSocket takes the account's access token as a URL query parameter |
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Nothing matches these filters. .
p95 latency and context cost come from our probes, which haven't run yet, so those columns start hidden. Grades run from AA to F, and agent-ready means BB or better. Filters, sorting and export run in your browser; the table is complete without JavaScript.
Indexed, not reviewed (20)
Listings sorted into this category from public catalogues (the official MCP registry, APIs.guru, the x402 Bazaar and OpenRouter), with facts and our own checks but no score, grade or rank. How the index works.
| Listing | Kind | What it does | Why it's here |
|---|---|---|---|
| 2kw.ai 2kw.ai | MCP server | EU-hosted AI platform: OpenAI-compatible LLM gateway, document extraction, transcription, agents. | vendor's own, widely used |
| backengine-mcp backengine.ai | MCP server | Surface customer & prospect context from Slack, email, transcripts and tickets in any MCP client. | vendor's own |
| Bigdata.com bigdata.com | MCP server | Licensed, cited financial data for AI agents: news, filings, transcripts, research and tearsheets. | vendor's own |
| Cleat cleat.so | MCP server | A real US mobile number that receives verification codes, by text or transcribed call. | vendor's own |
| clipy.online MCP server clipy.online | MCP server | Read your Clipy screen recordings: search, transcripts, AI summaries, and key moments with frames. | vendor's own |
| Cortex RMCP dinglebear.ai | MCP server | Rust MCP server for homelab logs, syslog, Docker logs, FTS search, and AI transcript correlation. | vendor's own |
| Crixin Voice crixin.com | MCP server | Give your AI a real phone: place calls, send SMS, fetch recordings and transcripts. Local or hosted. | vendor's own |
| DialMCP dialmcp.com | MCP server | Let AI agents place real phone calls from your verified number, with transcripts and recordings. | vendor's own |
| Gavelin gavelin.ai | MCP server | Search bills and speaker-attributed hearing transcripts across all 50 US state legislatures. | vendor's own |
| importly-mcp importly.io | MCP server | Download, transcribe, and get metadata for any video/audio URL. Managed yt-dlp + speech-to-text. | vendor's own |
| Memo AI – meeting assistant memoai.tech | MCP server | Search transcripts and summaries of your meetings, calls, and recordings in Memo AI | vendor's own |
| pepys-mcp pepys.co | MCP server | Transcribe audio & video: diarization, timed SRT/VTT, podcasts, paste-a-link, whole-feed batch. | vendor's own |
| Rephonic rephonic.com | MCP server | Research 3M+ podcasts with audience data, contacts, episodes, transcripts, charts, and sponsors. | vendor's own |
| SOAPNoteAPI soapnoteapi.com | MCP server | Generate clinical SOAP notes, billing codes, and visit summaries from transcripts or audio. | vendor's own |
| transcription www.scriptivox.com | MCP server | AI transcription from URLs or files. 119 languages, diarization, SRT/VTT/text export. | vendor's own |
| Vexa vexa.ai | MCP server | Meeting bot and transcripts for Google Meet, Teams and Zoom. Live or after, speakers labelled. | vendor's own, widely used |
| Video Extract yanlinglabs.com | MCP server | Download any video from a URL, or get its transcript and key frames. All local, no API keys. | vendor's own |
| Voxplo voxplo.ai | MCP server | Give AI agents a phone: outbound AI calls that return a summary, transcript, and extracted fields. | vendor's own |
| YouTube Transcript + YouTube Search MCP getyoutubetranscript.com | MCP server | YouTube transcripts, search, channel browsing, and playlists for AI agents via MCP. | vendor's own |
| 💯 YouTube Transcript + YouTube Search MCP for AI Agents transcriptapi.com | MCP server | 💯 The fastest YouTube transcript + YouTube search MCP for AI agents. Try for free. | vendor's own |
How we test this category
The same audio set through every API, with accents, background noise, proper names and overlapping speakers. We measure word error rate on each slice, streaming latency to a final transcript, and cost per audio minute. This test hasn't run yet, so Task success is pending and the grades here come from the categories assessed from public evidence.
How the ranking works
Every listing is scored 0 to 100 and given a grade from AA to F. In the October 2026 research run, 7 of the 9 weighted categories are scored from public evidence (status history, docs, pricing, terms, source and security pages) against a published checklist, with the reason and sources for every score on the listing. Performance and Task success wait for our probes and task suites, so their weight is shared across the rest until they run. Negative events deduct up to 15 points. Read the methodology.
For companies
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